Combustion Science and Technology, Vol.116, No.1-6, 455-478, 1996
Effects of copper contamination on dioxin emissions from CFC incineration
A test program was developed and implemented for investigating the effects of copper contamination on dioxin emissions from incinerating chlorofluorocarbons (CFCs). Experiments were performed using a turbulent flame reactor (TFR) with a capacity of 21 kW to investigate the effect of copper contamination in the combustor refractory on dioxin emissions. Distillate fuel oil doped with copper naphthenate was fired, followed by a copper nitrate solution which was injected into the TFR fired by natural gas, with 1 g/hr copper injection rate for a total of 20 hours prior to the incineration of the unused, pure CFC-12 (8.7 vol% CFC-12, 92.3 vol% propane fuel). High dioxin emissions (454 ng/dscm total polychlorinated dibenzo-p-dioxins and dibenzofurans) were observed. Subsequent firing of the TFR with the propane fuel for 54 hours reduced the dioxin emissions to about 386 ng/dscm during the following CFC-12 incineration test. The test results suggest that high dioxin emissions could be caused by a strong promotional effect when highly chlorinated wastes, such as CFCs, are incinerated in a facility on which the refractory is contaminated with trace levels of copper from the previous treatment of a cooper-containing waste. Incineration tests were also performed on a recovered CFC-11,refrigerant which contains 5 vol% residual oil (with 4 ppm copper contaminant in the oil). The test results show that the level of copper contaminant contained in the recovered CFC-11 is insufficient to cause dioxin emissions. The high levels (>99.999%) of destruction efficiency and the low levels of products of incomplete combustion (PICs) emissions from the incineration of the recovered CFC-11 are found to be very similar to those from the incineration of unused, pure CFCs.
Keywords:DIBENZO-P-DIOXINS;FLY-ASH